1. Field of the Invention
The present invention relates to a technology for forming an image on a recording medium that is fed from one of a plurality of feed paths in an image forming apparatus, and more particularly, to a technology for recovering from a paper jam in a feed path.
2. Description of the Related Art
Most of the image forming apparatuses including copiers and electrographic printers include a plurality of feed trays on which papers of different sizes are stacked. A paper is picked up from one of the feed trays and conveyed to an image forming unit through a corresponding one of a plurality of feed paths. A paper sensor is arranged in each of the feed paths to sense a paper passing through that feed path. When a sensor detects a paper jam, information about where the paper jam has occurred is displayed on a display unit for a user. Some of the image forming apparatuses additionally display a guidance screen on the display unit to guide the user how to remove the jammed paper.
Japanese Patent Application Laid-open No. 2007-62917 discloses a sheet conveyer and an image forming apparatus including the sheet conveyer, from which the user can easily remove a paper jammed near a registration roller. The sheet conveyer includes a registration guide member that is located upstream of the registration roller or a conveyer roller with respect to a sheet conveyer path. The registration guide member is supported in a rotatable manner around a fulcrum that is located upstream. With this configuration, the registration guide member can move between a first position at which the registration guide member works as a part of the sheet conveyer path and a second position at which the registration guide member makes the sheet conveyer path opened. Thus, the registration guide member can be turned easily, the range of movement of the registration guide member is also relatively large so that the sheet conveyer path can be opened widely. Therefore, the user can easily remove the jammed paper from the sheet conveyer.
There are several advantages in usage of multiple feed trays instead of a single feed tray. The first advantage is to decrease frequency of sheet setting by setting various types of recording media on the feed trays. If the single feed tray is used, the user has to set a desired-sized recording medium on a bypass tray each time the user uses. The second advantage is that, even if a paper jam occurs while the recording medium is conveyed from a first feed tray, it is possible to smoothly finish printing by feeding a recording medium from a second feed tray instead of the first feed tray. To improve productivity of the image forming apparatus by immediately recovering from the paper jam, a measure making full use of those advantages with the multiple feed trays will be effective.
The operation of the sheet conveyer disclosed in Japanese Patent Application Laid-open No. 2007-62917 must be stopped until the jammed paper is removed. This can lead to decrease in the productivity.